[Windows][Codex App] Existing project silently stops responding across all threads/models while new projects work

What version of the Codex App are you using?

Not captured yet. The issue is occurring in the current Windows Codex desktop app on 2026-09-14. I can add the exact version from the About dialog if needed.

What subscription do you have?

ChatGPT Pro.

What platform is your computer?

Windows desktop (Windows 11).

What issue are you seeing?

One existing local Codex project (LGC) has become completely unusable: prompts are accepted and appear in the conversation, but no assistant turn starts and no response is produced.

There is no visible error message. The prompt simply remains in the thread with nothing returned by Codex.

This is not isolated to one thread or one model:

• Multiple existing threads inside the same project show the same behavior.
• Multiple model selections show the same behavior, including GPT-6 Astra.
• A normal Codex chat opened outside any project responds correctly.
• A brand-new Codex Project created from a brand-new empty folder also responds correctly immediately.

This strongly suggests that the failure is isolated to the persisted state / workspace mapping / initialization state of one existing project rather than account connectivity, model availability, or the global Projects feature.

The affected project contains important long-running development context, so deleting the project, clearing all local Codex state, or recreating everything from scratch is not an acceptable recovery path.

Steps that reproduce the bug

1. Open Codex Desktop on Windows.
2. Open the existing local Project LGC.
3. Open any existing thread in that Project.
4. Send a simple prompt.
5. The user message appears in the thread, but Codex produces no assistant response and shows no actionable error.
6. Repeat in another thread inside the same Project: same result.
7. Change to another model: same result.
8. Open a normal non-Project Codex chat and send OK: it responds normally.
9. Create a completely new Project backed by a new empty folder and send OK: it responds normally.

Expected behavior

An existing Project should continue to initialize and execute turns normally. If its persisted state, workspace metadata, history projection, plugin/hook initialization, or thread mapping is corrupted, Codex should:

1. show a clear error instead of failing silently;
2. automatically recover or rebuild the project state when possible;
3. provide a supported repair/rebind mechanism that preserves project threads/history and does not require deleting .codex or recreating the whole project.

Actual behavior

The affected Project accepts messages but never starts/returns an assistant turn. There is no error and no recovery UI.

Scope isolation already performed

• Non-Project chat: works.
• New Project + new empty folder: works.
• Existing affected Project: fails.
• Multiple threads in affected Project: fail.
• Multiple models in affected Project: fail.

Because a new Project works in the same Codex installation, this does not appear to be a general network/account/model outage.

Additional information

A screenshot of the affected thread is available. It shows a submitted prompt visible in the existing Project with no assistant response beneath it.

Please investigate persisted per-project state / workspace-to-thread mapping and silent initialization failures on Windows. I can provide sanitized logs or additional diagnostics if maintainers specify exactly which supported files/commands are useful. I would prefer not to manually modify internal Codex databases or delete local state, because the affected Project contains important development history.

Start by reproducing the difference between the existing LGC project and a new empty-folder project on Windows. Investigate persisted per-project state, workspace-to-thread mapping, and project initialization failures using the sanitized logs or diagnostics maintainers request. Done means the affected project reports an actionable error or recovers through a supported repair path without deleting its threads or history.